RE: [APML] MF cameras, films and Tak scopes

["Gene Horr" <genehorr@houston.rr.com>]

-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Alan Voetsch

> Which brings up the question: why does 120 need paper for
> light-tightness and 220 does not? If it's necessary for one, seems
> like
> it would be necessary bor both. Obviously not, so I must have missed
> something basic.

The 220 has paper at the beginning and the end of the roll.  In 
the middle the film is in the camera, so the paper is not needed.
The paper was removed on the 220 design to allow the longer length 
of film to sit on the same sile reel.

> Is it the job of the camera back to determine how how long the film
> length is?

Sort of.  Most cameras have the exposure counter in the film back.
Otherwise you wouldn't know when you were out of film.

> I assume from this that very little (if any) 120 film is used by
> folks like us?

Well, actually a lot is.  I would guess that less than half the
astrophotographers have a vacuum back.

> Also, does the FS-128 have an advantage as far as the hot spot? Oh
> yeah, sorry, you haven't used one. Anyone? I'd guess it would be far
> less of an issue because of the f/8 tube. But does using the Tak
> reducer bring this up as an issue?

I haven't seen it.  One thing to keep in mind that with the FS128
and formats larger than 6x4.5 you'll need the 4" reducer.  Much
more $$$$.

Gene Horr
genehorr@houston.rr.com
 
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